Device-to-device user equipment for a wireless communication system and resource scheduling method thereof

ABSTRACT

A device to device (D2D) user equipment (UE) used for a wireless communication system is provided. The D2D UE is located in a network topology including a plurality of transmitting ends and a plurality of receiving ends. The D2D UE may be a transmitting end or a receiving end. The receiving ends perform a resource scheduling procedure several times according to transmitting end sequences echoed from the transmitting ends to schedule the appropriate resources for the transmitting ends so as to prevent a transmission collision.

PRIORITY

This application claims the benefit of priority based on U.S.Provisional Application Ser. No. 61/953,023 filed on Mar. 14, 2014,which is hereby incorporated by reference in its entirety.

FIELD

The present invention relates to a device-to-device (D2D) user equipment(UE) for a wireless communication system and a resource schedulingmethod thereof. More particularly, the D2D UE of the present inventionexecutes a resource scheduling procedure several times to avoidtransmission collisions.

BACKGROUND

As the wireless communication technologies become matured in recentyears, various wireless communication systems have been developed andwidely applied in people's daily life to satisfy the users' need forcommunication. Among these wireless communication systems, the 3GPP LTE(3^(rd) Generation Partnership Project Long Term Evolution)communication system has experienced the rapidest development.

In the 3GPP LTE communication system, UEs that are to transmit datatherebetween usually have to take a base station and a core network asmedia and transmit data via resources allocated by the base station.Although a concept of allowing the UEs to transmit data by directlycontending for wireless resources (i.e., device-to-device (D2D)communication) has been proposed in the art and the industry, theexisting contention-for-scheduling mechanisms all have a lot ofdrawbacks.

The existing contention-for-scheduling mechanisms are mainly dividedinto the purely distributed type and the central assistance type. Thepurely distributed type is based on the CSMA-CA (Carrier Sense MultipleAccess with Collision Avoidance) protocol or the ALOHA protocol, andallows distributed D2D UEs to obtain wireless resources necessary fordata transmission. However, the contention-for-scheduling mechanisms ofthe purely distributed type generally only allow contending for wirelessresources on the time axis, and leave much time idle, so the spectrumutilization efficiency is relatively limited.

Additionally, in the contention-for-scheduling mechanism of the centralassistance type, the base station needs to obtain the neighborshipbetween D2D UEs and wireless resources needed. In practice, there mightbe a lot of D2D UEs, so obtaining such information necessitates a largeamount of data exchanges. In such a case, having the base station beresponsible for the resource scheduling will cause an excessive burdenon the base station. Therefore, the contention-for-scheduling mechanismsof the central assistance type are difficult to be implemented.

Accordingly, an urgent need exists in the art to provide a resourcescheduling mechanism that allows D2D UEs to obtain wireless resourcesnecessary for direct mode communication with adjacent D2D UES in adistributed way in consideration of the spectrum utilization efficiency.

SUMMARY

Disclosed is a resource scheduling mechanism. The resource schedulingmechanism is based on the two-dimensional time-frequency contention, andallows D2D UEs to obtain wireless resources necessary for direct modecommunication with adjacent UEs in a distributed way. Thereby, ascompared with the conventional contending-for-scheduling mechanisms ofthe purely distributed type, the present invention can reduce the idletime and improve the spectrum utilization efficiency so as to improvethe quality of service (QoS).

Also disclosed is a device-to-device (D2D) user equipment (UE) for awireless communication system. The wireless communication system definesa scheduling channel, an echo channel and a plurality of data resourceblock sets. The scheduling channel comprises a plurality of schedulingresource blocks. The echo channel comprises a plurality of echo resourceblocks. The scheduling channel and the echo channel correspond to eachother. The scheduling resource blocks and the data resource block setscorrespond to each other. The D2D UE is located in a network topology.The network topology includes a plurality of transmitting ends and aplurality of receiving ends, and the D2D UE is one of the receivingends. The D2D UE comprises a transceiver, a storage, and a processor.The storage is configured to store a plurality of pieces of resourcedemand information and a plurality of priority values of thetransmitting ends as well as a plurality of transmitting end sequences.Each of the transmitting ends corresponds to one of the transmitting endsequences. The processor is electrically connected to the transceiverand the storage, and is configured to execute the following operations:generating a first resource scheduling result according to the resourcedemand information and the priority value of each of the transmittingends; sending one of the transmitting end sequences respectively in thescheduling resource blocks via the transceiver according to the firstresource scheduling result; receiving at least one of the transmittingend sequences respectively in the echo resource blocks via thetransceiver; generating a second resource scheduling result according tothe transmitting end sequences received from the echo resource blocksand the priority values; and sending one of the transmitting endsequences respectively in the scheduling resource blocks via thetransceiver according to the second resource scheduling result.

Further disclosed is a resource scheduling method for a D2D UE. The D2DUE is used in a wireless communication system and is located in anetwork topology. The network topology includes a plurality oftransmitting ends and a plurality of receiving ends. The D2D UE is oneof the receiving ends and comprises a transceiver, a storage and aprocessor. The storage is configured to store a plurality of pieces ofresource demand information and a plurality of priority values of thetransmitting ends, and a plurality of transmitting end sequences. Eachof the transmitting ends corresponds to one of the transmitting endsequences. The wireless communication system defines a schedulingchannel, an echo channel and a plurality of data resource block sets.The scheduling channel comprises a plurality of scheduling resourceblocks. The echo channel comprises a plurality of echo resource blocks.The scheduling channel and the echo channel correspond to each other.The scheduling resource blocks and the data resource block setscorrespond to each other. The resource scheduling method is executed bythe processor and comprises the following steps of: generating a firstresource scheduling result according to the resource demand informationand the priority value of each of the transmitting ends; sending one ofthe transmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the first resource schedulingresult; receiving at least one of the transmitting end sequencesrespectively in the echo resource blocks via the transceiver; generatinga second resource scheduling result according to the transmitting endsequences received from the echo resource blocks and the priorityvalues; and sending one of the transmitting end sequences respectivelyin the scheduling resource blocks via the transceiver according to thesecond resource scheduling result.

Additionally disclosed is a D2D UE for a wireless communication system.The wireless communication system defines a scheduling channel, an echochannel and a plurality of data resource block sets. The schedulingchannel comprises a plurality of scheduling resource blocks. The echochannel comprises a plurality of echo resource blocks. The schedulingchannel and the echo channel correspond to each other. The schedulingresource blocks and the data resource block sets correspond to eachother. The D2D UE is located in a network topology that includes aplurality of transmitting ends and a plurality of receiving ends, andthe D2D UE is one of the transmitting ends. The D2D UE comprises atransceiver, a storage and a processor. The storage is configured tostore a plurality of transmitting end sequences. The D2D UE correspondsto one of the transmitting end sequences. The processor is electricallyconnected to the transceiver and the storage, and is configured toexecute the following operations: (a) receiving at least one of thetransmitting end sequences respectively from the scheduling resourceblocks via the transceiver; (b) sending at least one of the transmittingend sequences respectively in the echo resource blocks via thetransceiver, wherein the at least one transmitting end sequencetransmitted in the echo resource blocks is the same as the at least onetransmitting end sequence received from the scheduling resource blocks;and (c) receiving at least one of the transmitting end sequencesrespectively again from the scheduling resource blocks via thetransceiver.

Further disclosed is a resource scheduling method for a D2D UE. The D2DUE is used in a wireless communication system and is located in anetwork topology. The network topology includes a plurality oftransmitting ends and a plurality of receiving ends. The D2D UE is oneof the transmitting ends and comprises a transceiver, a storage and aprocessor. The storage is configured to store a plurality oftransmitting end sequences. The D2D UE corresponds to one of thetransmitting end sequences. The wireless communication system defines ascheduling channel, an echo channel and a plurality of data resourceblock sets. The scheduling channel comprises a plurality of schedulingresource blocks. The echo channel comprises a plurality of echo resourceblocks. The scheduling channel and the echo channel correspond to eachother. The scheduling resource blocks and the data resource block setscorrespond to each other. The resource scheduling method is executed bythe processor and comprises the following steps of: (a) receiving atleast one of the transmitting end sequences respectively from thescheduling resource blocks via the transceiver; (b) sending at least oneof the transmitting end sequences respectively in the echo resourceblocks via the transceiver, wherein the at least one transmitting endsequence transmitted in the echo resource blocks is the same as the atleast one transmitting end sequence received from the schedulingresource blocks; and (c) receiving at least one of the transmitting endsequences respectively again from the scheduling resource blocks via thetransceiver.

The detailed technology and preferred embodiments implemented for thesubject invention are described in the following paragraphs accompanyingthe appended drawings for people skilled in this field to wellappreciate the features of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a network topology according to a firstembodiment of the present invention;

FIG. 1B depicts a scheduling channel SCH, an echo channel ECH and a dataresource block set DRBS_i according to the first embodiment of thepresent invention;

FIG. 1C depicts transmitting end sequences sent in the schedulingchannel SCH and transmitting end sequences received in the echo channelECH by the receiving ends RX1 and RX2 according to the first embodimentof the present invention;

FIG. 1D depicts transmitting end sequences received in the schedulingchannel SCH and transmitting end sequences sent in the echo channel ECHby the transmitting ends TX1 and TX2 according to the first embodimentof the present invention;

FIG. 2A is a schematic view of a network topology according to a secondembodiment of the present invention;

FIG. 2B depicts transmitting end sequences sent in the schedulingchannel SCH and transmitting end sequences received in the echo channelECH by the receiving end RX1 according to the second embodiment of thepresent invention;

FIG. 2C depicts transmitting end sequences sent in the schedulingchannel SCH and transmitting end sequences received in the echo channelECH by the receiving end RX2 according to the second embodiment of thepresent invention;

FIG. 2D depicts transmitting end sequences sent in the schedulingchannel SCH and transmitting end sequences received in the echo channelECH by the receiving end RX3 according to the second embodiment of thepresent invention;

FIG. 2E depicts transmitting end sequences received in the schedulingchannel SCH and transmitting end sequences sent in the echo channel ECHby the transmitting end TX1 according to the second embodiment of thepresent invention;

FIG. 2F depicts transmitting end sequences received in the schedulingchannel SCH and transmitting end sequences sent in the echo channel ECHby the transmitting end TX2 according to the second embodiment of thepresent invention;

FIG. 2G depicts transmitting end sequences received in the schedulingchannel SCH and transmitting end sequences sent in the echo channel ECHby the transmitting end TX3 according to the second embodiment of thepresent invention;

FIG. 2H depicts transmitting end sequences received in the schedulingchannel SCH and transmitting end sequences sent in the echo channel ECHby the transmitting end TX4 according to the second embodiment of thepresent invention;

FIG. 3 is a schematic view of a D2D UE according to a third embodimentto a sixth embodiment of the present invention;

FIG. 4 is a flowchart diagram of a resource scheduling method accordingto a seventh embodiment of the present invention; and

FIG. 5 is a flowchart diagram of a resource scheduling method accordingto an eighth embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, the present invention will be explainedwith reference to certain example embodiments thereof. It shall beappreciated that, these example embodiments are not intended to limitthe present invention to any specific example, embodiment, environment,applications or particular implementations described in theseembodiments. Therefore, description of these example embodiments is onlyfor purpose of illustration rather than to limit the present invention,and the scope of this application shall be governed by the claims.

In the following embodiments and the attached drawings, elementsunrelated to the present invention are omitted from depiction; anddimensional relationships among individual elements in the attacheddrawings are illustrated only for ease of understanding, but not tolimit the actual scale.

The D2D UE of the present invention is used in a wireless communicationsystem, and has a function of device-to-device direct modecommunication. The wireless communication system involved in the presentinvention may be a wireless communication system conforming to the LongTerm Evolution (LTE) standard or some other wireless communicationsystem such as a wireless communication system adopting the OrthogonalFrequency Division Multiplexing Access (OFDMA) communication technology.

A first embodiment of the present invention is shown in FIG. 1A, whichdepicts that there are two receiving ends RX1, RX2 and two transmittingends TX1 and TX2 in a region. The receiving ends RX1, RX2 and thetransmitting ends TX1 and TX2 form a network topology. The receiving endRX1 can receive signals transmitted by the transmitting ends TX1 andTX2, while the receiving end RX2 can only receive signals transmitted bythe transmitting end TX2. In detail, the transmitting end TX1 may not belocated within a signal coverage of the receiving end RX2, or the signaltransmission therebetween is blocked due to geographical environmentfactors. The receiving ends RX1, RX2 and the transmitting ends TX1 andTX2 are all the D2D UEs of the present invention.

The receiving end RX1 learns wireless resources necessary for datatransmission of the transmitting ends TX1 and TX2 and transmitting endindex values (e.g., connection identifications) of the transmitting endsTX1 and TX2 through receiving resource request messages from thetransmitting ends TX1 and TX2. After having learned the wirelessresources needed by the transmitting ends TX1, TX2 and the transmittingend index values, the receiving ends RX1 and RX2 generate and storeresource demand information and priority values of the transmitting endsTX1 and TX2. In this embodiment, the priority values of the transmittingends TX1 and TX2 are determined according to the transmitting end indexvalues of the transmitting ends TX1 and TX2, and the transmitting endwith a smaller transmitting end index value has a smaller priority value(e.g., the priority value of the transmitting end TX1 is 1, while thepriority value of the transmitting end TX2 is 2). In the followingdescriptions of this embodiment, the transmitting end with a smallerpriority value is preferentially allocated a resource block set.

Similarly, the receiving end RX2 learns wireless resources necessary fordata transmission of the transmitting end TX2 and the transmitting endindex value of the transmitting end TX2 through receiving a resourcerequest message from the transmitting end TX2. After having learned thewireless resources needed by the transmitting end TX2 and thetransmitting end index value, the receiving end RX2 generates and storesthe resource demand information and the priority value of thetransmitting end TX2. Additionally, the receiving ends RX1 and RX2further store a plurality of transmitting end sequences. Thetransmitting end index value of each of the transmitting ends TX1 andTX2 corresponds to one of the transmitting end sequences, so thetransmitting end TX1 is associated with the transmitting end sequenceTS1 and the transmitting end TX2 is associated with the transmitting endsequence TS2. The transmitting end sequences are sequences orthogonal toeach other, or the sequences able to be separately identifiable, e.g.,Zadoff-Chu sequences. It should be appreciated that, the receiving endsin this embodiment learn the wireless resources needed by thetransmitting ends and the transmitting end index values thereof throughreceiving the resource request messages from the transmitting ends.However, in other embodiments, the receiving ends may learn the wirelessresources needed by the surrounding transmitting ends and thetransmitting end index values thereof from a base station that they areconnecting to.

In this embodiment, the wireless resources may be in units of resourceblocks defined by the LTE wireless communication system, or in unitssimilar to the resource blocks defined by the LTE wireless communicationsystem. A resource block is a specific region formed by a time axis anda frequency axis. Because the composition of the resource block can bereadily appreciated by those of ordinary skill in the art, it will notbe further detailed herein.

The wireless communication system defines a scheduling channel SCH, anecho channel ECH and a plurality of data resource block sets DRBS_i. Forexample, as shown in FIG. 1B, the scheduling channel SCH comprises sixscheduling resource blocks SRB1˜SRB6, and the echo channel ECH comprisessix echo resource blocks ERB1˜ERB6. The scheduling channel SCH and theecho channel ECH correspond to each other (i.e., SRB1 corresponds toERB1, and SRB2 corresponds to ERB2 and so on). The scheduling channelSCH and the echo channel ECH appear alternately with time, and the twocan be located in a same frequency band or in different frequency bands.For example, the scheduling channel SCH and the echo channel ECH appearin different subframes alternately, and the frequency bands occupied bythe two in the respective subframes may be the same or different.

The scheduling resource blocks SRB1˜SRB6 correspond to six differentdata resource block sets DRBS_i respectively, and each of the dataresource block sets DRBS_i comprises a plurality of resource blocks. Forexample, each of the data resource block sets DRBS_i comprises ten dataresource blocks DRB1˜DRB10, and the scheduling resource blocks SRB1˜SRB6correspond to the data resource block sets DRBS_1˜DRBS_6 respectively.The data resource block sets may be adjacent to each other or bedistributed. It shall be appreciated that, the number of schedulingresource blocks comprised in the aforesaid scheduling channel SCH, thenumber of echo resource blocks comprised in the echo channel ECH, thenumber of data resource block sets, and the number of resource blockscomprised in each of the data resource block sets are provided only forpurpose of illustration rather than to limit the scope of the presentinvention.

In the network topology of FIG. 1A, the maximum and farthest hop numberof the network topology is 3 (i.e., 2N+1, where N=1), so the receivingends RX1 and RX2 of this embodiment need to perform the resourcescheduling procedure twice times (i.e. N+1 times). The receiving endsRX1, RX2 and the transmitting ends TX1 and TX2 connect to a backhaulnetwork server (not depicted) via base stations (not depicted) that theyare respectively connecting to. The backhaul network server decides themaximum and farthest hop number 2N+1 and informs the transmitting endsTX1, TX2 and the receiving ends RX1 and RX2 of this.

The receiving end RX1 performs a first resource scheduling procedureaccording to the resource demand information and the priority values ofthe transmitting ends TX1 and TX2. Herein, suppose that the transmittingend TX1 needs two data resource block sets for data transmission and thetransmitting end TX2 needs three data resource block sets for datatransmission. Thus, the receiving end RX1 informs the transmitting endsTX1 and TX2 of a first resource scheduling result of the first resourcescheduling procedure via the scheduling resource blocks SRB1˜SRB6 of thescheduling channel SCH. Similarly, the receiving end RX2 performs thefirst resource scheduling procedure according to the resource demandinformation and the priority value of the transmitting end TX2, andinforms the transmitting end TX2 of the first resource scheduling resultof the first resource scheduling procedure via the scheduling resourceblocks SRB1˜SRB6 of the scheduling channel SCH.

As previously described, the transmitting end with a smaller priorityvalue is preferentially allocated a resource block set; that is, thesmaller the priority value is, the higher the priority level will be.Therefore, the receiving end firstly allocates the data resource blockset DRBS_i with a smaller serial number to the transmitting end with asmaller priority value. As shown in FIG. 1C, in the first resourcescheduling result of the first resource scheduling procedure, thereceiving end RX1 allocates the data resource block sets DRBS_1˜DRBS_2to the transmitting end TX1, and allocates the data resource block setsDRBS_3˜DRBS_5 to the transmitting end TX2. Then, the receiving end RX1sends the transmitting end sequence TS1 in the scheduling resourceblocks SRB1˜SRB2 of the scheduling channel SCH, and sends thetransmitting end sequence TS2 in the scheduling resource blocksSRB3˜SRB5. On the other hand, in the first resource scheduling result ofthe first resource scheduling procedure, the receiving end RX2 allocatesthe data resource block sets DRBS_1˜DRBS_3 to the transmitting end TX2.Then, the receiving end RX2 sends the transmitting end sequence TS2 inthe scheduling resource blocks SRB1˜SRB3 of the scheduling channel SCH.

Afterwards, as shown in FIG. 1D, the transmitting end TX1 receives thetransmitting end sequence TS1 in the scheduling resource blocksSRB1˜SRB2 of the scheduling channel SCH, and receives the transmittingend sequence TS2 in the scheduling resource blocks SRB3˜SRB5 of thescheduling channel SCH. Then, the transmitting end TX1 sends thetransmitting end sequences, which are received by the transmitting endTX1 in the scheduling channel SCH, via the echo channel ECH (i.e., tosend the transmitting end sequence TS1 in the echo resource blocksERB1˜ERB2 and send the transmitting end sequence TS2 in the echoresource blocks ERB3˜ERB5). Similarly, the transmitting end TX2 receivesthe transmitting end sequence TS2 in the scheduling resource blocksSRB1˜SRB3 of the scheduling channel SCH. Then, the transmitting end TX2sends the transmitting end sequence, which is received by thetransmitting end TX2 in the scheduling channel SCH, via the echo channelECH (i.e., to send the transmitting end sequence TS2 in the echoresource blocks ERB1˜ERB3).

Next, the receiving end RX1 performs a second resource schedulingprocedure, and determines whether there are two or more transmitting endsequences in the echo resource blocks ERB1˜ERB6 of the echo channel ECH.If the determination result is “yes”, it means that there is a dataresource block set DRBS_i that is allocated to the transmitting ends TX1and TX2 simultaneously, so the scheduling resource blocks for sendingthe transmitting end sequences TS1, TS2 need to be further adjustedaccording to the priority values of the transmitting ends TX1 and TX2.Otherwise, if the answer is “no”, there is no need for the receiving endRX1 to make any adjustment. In this embodiment, the transmitting endsequences TS1 and TS2 are received by the receiving end RX1simultaneously in the echo resource blocks ERB1˜ERB2 of the echo channelECH. Therefore, the receiving end RX1 further determines that thepriority value of the transmitting end TX1 is smaller than that of thetransmitting end TX2 and, thus, decides to still allocate the dataresource block sets DRSB_1˜DRBS_2 to the transmitting end TX1. Then,according to the second resource scheduling result of the secondresource scheduling procedure, the receiving end RX1 still allocates thedata resource block sets DRBS_1˜DRBS_2 to the transmitting end TX1, andallocates the data resource block sets DRBS_3˜DRBS_5 to the transmittingend TX2. Finally, the receiving end RX1 sends the transmitting endsequence TS1 in the scheduling resource blocks SRB1˜SRB2 of thescheduling channel SCH, and sends the transmitting end sequence TS2 inthe scheduling resource blocks SRB3˜SRB5.

On the other hand, the receiving end RX2 also performs the secondresource scheduling procedure, and determines whether there are two ormore transmitting end sequences in the echo resource blocks ERB1˜ERB6 ofthe echo channel ECH. In this embodiment, the transmitting end sequencesTS1 and TS2 are also received by the receiving end RX2 simultaneously inthe echo resource blocks ERB1˜ERB2 of the echo channel ECH, so thereceiving end RX2 further determines that the priority value of thetransmitting end TX2 is greater than that of the transmitting end TX1.Therefore, the first resource scheduling result of the first resourcescheduling procedure needs to be adjusted by skipping the data resourceblock sets DRBS_1˜DRBS_2 and allocating the data resource block setsDRBS_3˜DRBS_5 with greater serial numbers to the transmitting end TX2.Then, the receiving end RX2 sends the transmitting end sequence TS2 inthe scheduling resource blocks SRB3˜SRB5 of the scheduling channel SCHaccording to the second resource scheduling result of the secondresource scheduling procedure.

Accordingly, the transmitting end TX1 can perform data transmissionthrough the use of the data resource block sets DRBS_1˜DRBS_2 accordingto the transmitting end sequence TS1 of the scheduling resource blocksSRB1˜SRB2, and the transmitting end TX2 can perform data transmissionthrough the use of the data resource block sets DRBS_3˜DRBS_5 accordingto the transmitting end sequence TS2 of the scheduling resource blocksSRB3˜SRB5. As can be known from this, through the first resourcescheduling procedure and the second resource scheduling proceduredescribed above, the present invention allocates data resource blocksets DRBS_i with greater serial numbers to transmitting ends withgreater priority values, so it can be avoided that a same data resourceblock set DRBS_i is allocated by the receiving ends RX1 and RX2 to thetransmitting ends TX1 and TX2 simultaneously.

A second embodiment of the present invention is shown in FIG. 2A, whichdepicts that there are three receiving ends RX1, RX2, RX3 and fourtransmitting ends TX1, TX2, TX3 and TX4 in a region. The receiving endRX1 can receive signals transmitted by the transmitting ends TX1 andTX2; the receiving end RX2 can receive signals transmitted by thetransmitted ends TX2 and TX3; and the receiving end RX3 can receivesignals transmitted by the transmitted ends TX3 and TX4. The receivingends RX1, RX2, RX3 and the transmitting ends TX1, TX2, TX3 and TX4 areall the D2D UEs of the present invention.

In the network topology of FIG. 2A, the maximum and farthest hop numberis 5 (i.e., 2N+1, where N=2), so the receiving ends RX1, RX2 and RX3 ofthis embodiment need to perform the resource scheduling procedure threetimes (i.e. N+1 times). For purpose of simplicity, the followingdescription will be made with reference to FIGS. 2B-2H for each of thereceiving ends RX1, RX2, RX3 and each of the transmitting ends TX1, TX2,TX3, TX4 in the scheduling channel SCH and the echo channel ECH duringrespective resource scheduling procedure stages. Moreover, it issupposed herein that the transmitting ends TX1, TX2, TX3 and TX4respectively need two, one, two and one data resource block set for datatransmission and the priority values of the transmitting ends TX1, TX2,TX3, and TX4 are 1, 2, 3, and 4 respectively.

Referring firstly to FIG. 2B, in the first resource schedulingprocedure, the receiving end RX1 allocates the data resource block setsDRBS_1˜DRBS_2 to the transmitting end TX1, and allocates the dataresource block set DRBS_3 to the transmitting end TX2. Then, thereceiving end RX1 sends the transmitting end sequence TS1 in thescheduling resource blocks SRB1˜SRB2, and sends the transmitting endsequence TS2 in the scheduling resource block SRB3. Afterwards, thereceiving end RX1 receives the transmitting end sequences TS1 and TS2simultaneously in the echo resource block ERB1, receives thetransmitting end sequences TS1 and TS3 simultaneously in the echoresource block ERB2, and receives the transmitting end sequences TS2 andTS3 simultaneously in the echo resource block ERB3.

Next, in the second resource scheduling procedure, the receiving end RX1determines whether each of the echo resource blocks comprises two ormore transmitting end sequences, and adjusts the transmitting endsequences sent in the scheduling resource blocks according to thepriority values of the transmitting ends corresponding to thetransmitting end sequences. Accordingly, in the second resourcescheduling procedure, the receiving end RX1 allocates the data resourceblock sets DRBS_1˜DRBS_2 to the transmitting end TX1, and allocates thedata resource block set DRBS_3 to the transmitting end TX2. Afterwards,the receiving end RX1 sends the transmitting end sequence TS1 in thescheduling resource blocks SRB1˜SRB2, and sends the transmitting endsequence TS2 in the scheduling resource block SRB3. Then, the receivingend RX1 receives the transmitting end sequence TS1 in the echo resourceblocks ERB1 and ERB2, receives the transmitting end sequence TS2 in theecho resource block ERB3, and receives the transmitting end sequence TS3in the echo resource blocks ERB4 and ERB5.

Finally, in the third resource scheduling procedure, the receiving endRX1 determines that each of the echo resource blocks has only onetransmitting end sequence, so the second resource scheduling result ofthe second resource scheduling procedure remains unchanged: that is, thedata resource block sets DRBS_1˜DRBS_2 are allocated to the transmittingend TX1, the data resource block set DRBS_3 is allocated to thetransmitting end TX2, the transmitting end sequence TS1 is sent in thescheduling resource blocks SRB1˜SRB2, and the transmitting end sequenceTS2 is sent in the scheduling resource block SRB3.

Referring to FIG. 2C, in the first resource scheduling procedure, thereceiving end RX2 allocates the data resource block set DRBS_1 to thetransmitting end TX2, and allocates the data resource block setsDRBS_2˜DRBS_3 to the transmitting end TX3. Then, the receiving end RX2sends the transmitting end sequence TS2 in the scheduling resource blockSRB1, and sends the transmitting end sequence TS3 in the schedulingresource blocks SRB2˜SRB3. Afterwards, the receiving end RX2 receivesthe transmitting end sequences TS1, TS2 and TS3 simultaneously in theecho resource block ERB1, receives the transmitting end sequences TS1and TS3 simultaneously in the echo resource block ERB2, and receives thetransmitting end sequences TS2, TS3 and TS4 simultaneously in the echoresource block ERB3.

Then, in the second resource scheduling procedure, the receiving end RX2determines whether each of the echo resource blocks comprises two ormore transmitting end sequences, and adjusts the transmitting endsequences sent in the scheduling resource blocks according to thepriority values of the transmitting ends corresponding to thetransmitting end sequences. Accordingly, in the second resourcescheduling procedure, the receiving end RX2 allocates the data resourceblock set DRBS_3 to the transmitting end TX2, and allocates the dataresource block sets DRBS_4˜DRBS_5 to the transmitting end TX3. Then, thereceiving end RX2 sends the transmitting end sequence TS2 in thescheduling resource block SRB3, and sends the transmitting end sequenceTS3 in the scheduling resource blocks SRB4˜SRB5. Afterwards, thereceiving end RX2 receives the transmitting end sequence TS1 in the echoresource block ERB1, receives the transmitting end sequences TS1 and TS3simultaneously in the echo resource block ERB2, receives thetransmitting end sequences TS2 and TS3 simultaneously in the echoresource block ERB3, receives the transmitting end sequences TS3 and TS4simultaneously in the echo resource block ERB4, and receives thetransmitting end sequence TS3 in the echo resource block ERB5.

Finally, in the third resource scheduling procedure, the receiving endRX2 determines whether each of the echo resource blocks comprises two ormore transmitting end sequences and, according to the priority values ofthe transmitting ends, determines whether the scheduling resource blocksfor sending the transmitting end sequences need to be adjusted. Becausethe priority value of the transmitting end TX2 is smaller than thepriority value of the transmitting end TX3 which, in turn, is smallerthan that of the transmitting end TX4, the receiving end RX2 keeps thesecond resource scheduling result of the second resource schedulingprocedure unchanged: that is, the data resource block set DRBS_3 isallocated to the transmitting end TX2, the data resource block setsDRBS_4˜DRBS_5 are allocated to the transmitting end TX3, thetransmitting end sequence TS2 is sent in the scheduling resource blockSRB3, and the transmitting end sequence TS3 is sent in the schedulingresource blocks SRB4˜SRB5.

Referring to FIG. 2D, in the first resource scheduling procedure, thereceiving end RX3 allocates the data resource block sets DRBS_1˜DRBS_2to the transmitting end TX3, and allocates the data resource block setDRBS_3 to the transmitting end TX4. Then, the receiving end RX3 sendsthe transmitting end sequence TS3 in the scheduling resource blocksSRB1˜SRB2, and sends the transmitting end sequence TS4 in the schedulingresource block SRB3. Afterwards, the receiving end RX3 receives thetransmitting end sequences TS2 and TS3 simultaneously in the echoresource block ERB1, receives the transmitting end sequence TS3 in theecho resource block ERB2, and receives the transmitting end sequencesTS3 and TS4 simultaneously in the echo resource block ERB3.

Then, in the second resource scheduling procedure, the receiving end RX3determines whether each of the echo resource blocks comprises two ormore transmitting end sequences, and adjusts the transmitting endsequences sent in the scheduling resource blocks according to thepriority values of the transmitting ends corresponding to thetransmitting end sequences. Accordingly, in the second resourcescheduling procedure, the receiving end RX3 allocates the data resourceblock sets DRBS_2˜DRBS_3 to the transmitting end TX3, and allocates thedata resource block set DRBS_4 to the transmitting end TX4. Afterwards,the receiving end RX3 sends the transmitting end sequence TS3 in thescheduling resource blocks SRB2˜SRB3, and sends the transmitting endsequence TS4 in the scheduling resource block SRB4. Then, the receivingend RX3 receives the transmitting end sequence TS3 in the echo resourceblock ERB2, receives the transmitting end sequences TS2 and TS3simultaneously in the echo resource block ERB3, receives thetransmitting end sequences TS3 and TS4 simultaneously in the echoresource block ERB4, and receives the transmitting end sequence TS3 inthe echo resource block ERB5.

Finally, in the third resource scheduling procedure, the receiving endRX3 determines whether each of the echo resource blocks comprises two ormore transmitting end sequences and, according to the priority values ofthe transmitting ends, determines whether the scheduling resource blocksfor sending the transmitting end sequences need to be adjusted. Becausethe priority value of the transmitting end TX2 is smaller than thepriority value of the transmitting end TX3 which, in turn, is smallerthan that of the transmitting end TX4, the receiving end RX3 adjusts thesecond resource scheduling result of the second resource schedulingprocedure so that the data resource block sets DRBS_4˜DRBS_5 areallocated to the transmitting end TX3, the data resource block setDRBS_6 is allocated to the transmitting end TX4, the transmitting endsequence TS3 is sent in the scheduling resource blocks SRB4˜SRB5, andthe transmitting end sequence TS4 is sent in the scheduling resourceblock SRB6.

Referring to FIG. 2E, in response to the first resource schedulingresult of the receiving end RX1, the transmitting end TX1 receives thetransmitting end sequence TS1 in the scheduling resource blocksSRB1˜SRB2 and receives the transmitting end sequence TS2 in thescheduling resource block SRB3. Then, the transmitting end TX1 sends thetransmitting end sequences, which are received by the transmitting endTX1 in the scheduling channel SCH, via the echo channel ECH (i.e., tosend the transmitting end sequence TS1 in the echo resource blocksERB1˜ERB2 and send the transmitting end sequence TS2 in the echoresource block ERB3).

Afterwards, in response to the second resource scheduling result of thereceiving end RX1, the transmitting end TX1 still receives thetransmitting end sequence TS1 in the scheduling resource blocksSRB1˜SRB2, and receives the transmitting end sequence TS2 in thescheduling resource block SRB3. Likewise, the transmitting end TX1 sendsthe transmitting end sequences, which are received by the transmittingend TX1 in the scheduling channel SCH, via the echo channel ECH (i.e.,to send the transmitting end sequence TS1 in the echo resource blocksERB1˜ERB2 and send the transmitting end sequence TS2 in the echoresource block ERB3). Finally, in response to the third resourcescheduling result of the receiving end RX1, the transmitting end TX1receives the transmitting end sequence TS1 in the scheduling resourceblocks SRB1˜SRB2 and receives the transmitting end sequence TS2 in thescheduling resource block SRB3 again.

Referring to FIG. 2F, in response to the first resource schedulingresult of the receiving ends RX1 and RX2, the transmitting end TX2receives the transmitting end sequences TS1 and TS2 simultaneously inthe scheduling resource block SRB1, receives the transmitting endsequences TS1 and TS3 simultaneously in the scheduling resource blockSRB2, and receives the transmitting end sequences TS2 and TS3simultaneously in the scheduling resource block SRB3. Then, thetransmitting end TX2 sends the transmitting end sequences, which arereceived by the transmitting end TX2 in the scheduling channel SCH, viathe echo channel ECH (i.e., to send the transmitting end sequences TS1and TS2 in the echo resource block ERB1, send the transmitting endsequences TS1 and TS3 in the echo resource block ERB2, and send thetransmitting end sequences TS2 and TS3 in the echo resource block ERB3).

Afterwards, in response to the second resource scheduling result of thereceiving ends RX1 and RX2, the transmitting end TX2 receives thetransmitting end sequence TS1 in the scheduling resource blocksSRB1˜SRB2, receives the transmitting end sequence TS2 in the schedulingresource block SRB3, and receives the transmitting end sequence TS3 inthe scheduling resource blocks SRB4˜SRB5. Then, the transmitting end TX2sends the transmitting end sequences, which are received by thetransmitting end TX2 in the scheduling channel SCH, via the echo channelECH (i.e., to send the transmitting end sequence TS1 in the echoresource blocks ERB1˜ERB2, send the transmitting end sequence TS2 in theecho resource block ERB3, and send the transmitting end sequence TS3 inthe echo resource blocks ERB4˜ERB5). Finally, in response to the thirdresource scheduling result of the receiving ends RX1 and RX2, thetransmitting end TX2 receives the transmitting end sequence TS1 in thescheduling resource blocks SRB1˜SRB2, receives the transmitting endsequence TS2 in the scheduling resource block SRB3, and receives thetransmitting end sequence TS3 in the scheduling resource blocksSRB4˜SRB5.

Referring to FIG. 2G, in response to the first resource schedulingresult of the receiving ends RX2 and RX3, the transmitting end TX3receives the transmitting end sequences TS2 and TS3 simultaneously inthe scheduling resource block SRB1, receives the transmitting endsequence TS3 in the scheduling resource block SRB2, and receives thetransmitting end sequences TS3 and TS4 simultaneously in the schedulingresource block SRB3. Then, the transmitting end TX3 sends thetransmitting end sequences, which are received by the transmitting endTX3 in the scheduling channel SCH, via the echo channel ECH (i.e., tosend the transmitting end sequences TS2 and TS3 in the echo resourceblock ERB1, send the transmitting end sequence TS3 in the echo resourceblock ERB2, and send the transmitting end sequences TS3 and TS4 in theecho resource block ERB3).

Afterwards, in response to the second resource scheduling result of thereceiving ends RX2 and RX3, the transmitting end TX3 receives thetransmitting end sequence TS3 in the scheduling resource block SRB2,receives the transmitting end sequences TS2 and TS3 simultaneously inthe scheduling resource block SRB3, receives the transmitting endsequences TS3 and TS4 simultaneously in the scheduling resource blockSRB4, and receives the transmitting end sequence TS3 in the schedulingresource block SRB5. Then, the transmitting end TX3 sends thetransmitting end sequences, which are received by the transmitting endTX3 in the scheduling channel SCH, via the echo channel ECH (i.e., tosend the transmitting end sequence TS3 in the echo resource block ERB2,send the transmitting end sequences TS2 and TS3 in the echo resourceblock ERB3, send the transmitting end sequences TS3 and TS4 in the echoresource block ERB4, and send the transmitting end sequence TS3 in theecho resource block ERB5). Finally, in response to the third resourcescheduling result of the receiving ends RX2 and RX3, the transmittingend TX3 receives the transmitting end sequence TS2 in the schedulingresource block SRB3, receives the transmitting end sequence TS3 in thescheduling resource blocks SRB4˜SRB5, and receives the transmitting endsequence TS4 in the scheduling resource block SRB6.

Referring to FIG. 2H, in response to the first resource schedulingresult of the receiving end RX3, the transmitting end TX4 receives thetransmitting end sequence TS3 in the scheduling resource blocksSRB1˜SRB2, and receives the transmitting end sequence TS4 in thescheduling resource block SRB3. Then, the transmitting end TX4 sends thetransmitting end sequences, which are received by the transmitting endTX4 in the scheduling channel SCH, via the echo channel ECH (i.e., tosend the transmitting end sequence TS3 in the echo resource blocksERB1˜ERB2 and send the transmitting end sequence TS4 in the echoresource block ERB3).

Afterwards, in response to the second resource scheduling result of thereceiving end RX3, the transmitting end TX4 receives the transmittingend sequence TS3 in the scheduling resource blocks SRB2˜SRB3, andreceives the transmitting end sequence TS4 in the scheduling resourceblock SRB4. Then, the transmitting end TX3 sends the transmitting endsequences, which are received by the transmitting end TX3 in thescheduling channel SCH, via the echo channel ECH (i.e., to send thetransmitting end sequence TS3 in the echo resource blocks ERB2˜ERB3 andsend the transmitting end sequence TS4 in the echo resource block ERB4).Finally, in response to the third resource scheduling result of thereceiving end RX3, the transmitting end TX4 receives the transmittingend sequence TS3 in the scheduling resource blocks SRB4˜SRB5, andreceives the transmitting end sequence TS4 in the scheduling resourceblock SRB6.

Accordingly, the transmitting end TX1 can use the data resource blocksets DRBS_1˜DRBS_2 for data transmission according to the transmittingend sequence TS1 of the scheduling resource blocks SRB1˜SRB2; thetransmitting end TX2 can use the data resource block set DRBS_3 for datatransmission according to the transmitting end sequence TS2 of thescheduling resource block SRB3; the transmitting end TX3 can use thedata resource block sets DRBS_4˜DRBS_5 for data transmission accordingto the transmitting end sequence TS3 of the scheduling resource blocksSRB4˜SRB5; and the transmitting end TX4 can use the data resource blockset DRBS_6 for data transmission according to the transmitting endsequence TS4 of the scheduling resource block SRB6. As can be known fromthis, through the first to the third resource scheduling proceduresdescribed above, the present invention can avoid that the receiving endsRX1, RX2 and RX3 allocate a same data resource block set DRBS_i todifferent transmitting ends simultaneously.

A third embodiment of the present invention is shown in FIG. 3, which isa schematic view of a D2D UE 1. The D2D UE 1 is used in a wirelesscommunication system, and comprises a storage 11, a processor 13 and atransceiver 15. The storage 11 is configured to store a plurality ofpieces of resource demand information and a plurality of priority valuesof a plurality of transmitting ends as well as a plurality oftransmitting end sequences. The resource demand information of each ofthe transmitting ends indicates the wireless resource needed by thetransmitting end to transmit data. The processor 13 is electricallyconnected to the storage 11 and the transceiver 15. As described in theprevious embodiments, the wireless communication system defines ascheduling channel, an echo channel and a plurality of data resourceblock sets. The scheduling channel comprises a plurality of schedulingresource blocks, and the echo channel comprises a plurality of echoresource blocks. The scheduling channel and the echo channel correspondto each other, and the scheduling resource blocks and the data resourceblock sets correspond to each other.

Specifically, the D2D UE 1 is located in a network topology thatincludes a plurality of transmitting ends and a plurality of receivingends. These receiving ends and transmitting ends are all D2D UEs, andhave functions identical to those of the D2D UE 1. The network topologyhas a maximum and farthest hop number of 2N+1, where N is a naturalnumber. In this embodiment, the maximum and farthest hop number is 3, soN is 1. The D2D UE 1 is a receiving end, which may be either of thereceiving ends RX1 and RX2 of the first embodiment.

The processor 13 generates a first resource scheduling result accordingto the resource demand information and the priority value of each of thetransmitting ends. Then, the processor 13 sends one of the transmittingend sequences respectively in the scheduling resource blocks via thetransceiver 15 according to the first resource scheduling result. Forexample, when the D2D UE 1 is the receiving end RX1 of the firstembodiment, the processor 13 sends the transmitting end sequence TS1 inthe scheduling resource blocks SRB1˜SRB2, and sends the transmitting endsequence TS2 in the scheduling resource blocks SRB3˜SRB5 via thetransceiver 15. Afterwards, the processor 13 receives at least one ofthe transmitting end sequences respectively in the echo resource blocksvia the transceiver 15. For example, when the D2D UE 1 is the receivingend RX1 of the first embodiment, the processor 13 receives thetransmitting end sequences TS1 and TS2 simultaneously in the echoresource blocks ERB1˜ERB2, and receives the transmitting end sequenceTS2 in the echo resource blocks ERB3˜ERB5 via the transceiver 15.

Then, the processor 13 generates a second resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values, and sends one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver 15 according to the second resourcescheduling result. For example, when the D2D UE 1 is the receiving endRX1 of the first embodiment, the processor 13 sends the transmitting endsequence TS1 in the scheduling resource blocks SRB1˜SRB2, and sends thetransmitting end sequence TS2 in the scheduling resource blocksSRB3˜SRB5 via the transceiver 15.

Please also refer to FIG. 3 for a fourth embodiment of the presentinvention. Different from the third embodiment, the D2D UE 1 of thefourth embodiment is located in a network topology, and the networktopology has a maximum and farthest hop number of 2N+1, where N isgreater than 1. Besides executing the operations described in the thirdembodiment, the processor 13 in this embodiment further executes thefollowing operations for N−1 times, and i is 2 to N: receiving at leastone of the transmitting end sequences respectively in the echo resourceblocks via the transceiver; generating a (i+1)^(th) resource schedulingresult according to the transmitting end sequences received from theecho resource blocks and the priority values; and sending one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the (i+1)^(th) resourcescheduling result.

Take a case where the D2D UE 1 is the receiving end RX2 of the secondembodiment and N=2 as an example. The processor 13 generates a firstresource scheduling result according to the resource demand informationand the priority value of each of the transmitting ends and, accordingto the first resource scheduling result, sends the transmitting endsequence TS2 in the scheduling resource block SRB1 and sends thetransmitting end sequence TS3 in the scheduling resource blocksSRB2˜SRB3 via the transceiver 15. Afterwards, the processor 13 receivesthe transmitting end sequences TS1, TS2 and TS3 simultaneously in theecho resource block ERB1, receives the transmitting end sequences TS1and TS3 simultaneously in the echo resource block ERB2, and receives thetransmitting end sequences TS2, TS3 and TS4 simultaneously in the echoresource block ERB3 via the transceiver 15.

Then, the processor 13 generates a second resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values and, according to the secondresource scheduling result, sends the transmitting end sequence TS2 inthe scheduling resource block SRB3 and sends the transmitting endsequence TS3 in the scheduling resource blocks SRB4˜SRB5 via thetransceiver 15. Then, the processor 13 receives the transmitting endsequence TS1 in the echo resource block ERB1, receives the transmittingend sequences TS1 and TS3 simultaneously in the echo resource blockERB2, receives the transmitting end sequences TS2 and TS3 simultaneouslyin the echo resource block ERB3, receives the transmitting end sequencesTS3 and TS4 simultaneously in the echo resource block ERB4, and receivesthe transmitting end sequence TS3 in the echo resource block ERB5 viathe transceiver 15. Finally, the processor 13 generates a third resourcescheduling result according to the transmitting end sequences receivedfrom the echo resource blocks and the priority values and, according tothe third resource scheduling result, sends the transmitting endsequence TS2 in the scheduling resource block SRB3 and sends thetransmitting end sequence TS3 in the scheduling resource blocksSRB4˜SRB5 via the transceiver 15.

In other embodiments, besides further executing the aforesaid operationsfor N−1 times, the processor 13 may further execute the aforesaidoperations for M times more, where M represents an adjustment number andis a natural number. In other words, the processor 13 further executesthe following operations for N+M−1 times, and i is 2 to N+M: receivingat least one of the transmitting end sequences respectively in the echoresource blocks via the transceiver; generating a (i+1)^(th) resourcescheduling result according to the transmitting end sequences receivedfrom the echo resource blocks and the priority values; and sending oneof the transmitting end sequences respectively in the schedulingresource blocks via the transceiver according to the (i+1)^(th) resourcescheduling result.

The adjustment number M may be decided by the backhaul network server,and is informed to each of the transmitting ends and the receiving ends;or may be decided by the processor 13 through executing an adjustmentprocedure. For example, the adjustment number M may be decided by thebackhaul network server according to a fact that there is a D2D UEmoving at a high speed in the network topology so as to avoid that thewireless resources can not be appropriately allocated to thetransmitting ends due to an insufficient number of times of the resourcescheduling procedure being executed by the receiving ends when a changein the maximum and farthest hop number is caused by the D2D UE moving ata high speed. Additionally, in the adjustment procedure, the processor13 may also determine that the D2D UE 1 itself or one of surrounding D2DUEs is moving at a high speed, decide the adjustment number Mcorrespondingly, and then informs the adjustment number M to each of thetransmitting ends and the receiving ends via the backhaul networkserver.

Please also refer to FIG. 3 for a fifth embodiment of the presentinvention. In this embodiment, the maximum and farthest hop number is 3,so N is 1. The D2D UE 1 is a transmitting end, which may be either ofthe receiving ends TX1 and TX2 of the first embodiment. The processor 13executes the following operations: (a) receive at least one of thetransmitting end sequences respectively from the scheduling resourceblocks via the transceiver 15; (b) transmit at least one of thetransmitting end sequences respectively in the echo resource blocks viathe transceiver 15, where the at least one transmitting end sequencetransmitted in the echo resource blocks is the same as the at least onetransmitting end sequence received from the scheduling resource blocks;and (c) receive at least one of the transmitting end sequencesrespectively from the scheduling resource blocks via the transceiver 15again.

Taking the receiving end TX2 of the first embodiment as an example, theprocessor 13 receives the transmitting end sequences TS1 and TS2simultaneously from the scheduling resource blocks SRB1˜SRB2, andreceives the transmitting end sequence TS2 from the scheduling resourceblocks SRB3˜SRB4 via the transceiver 15. Then, the processor 13 sendsthe transmitting end sequences TS1 and TS2 in the echo resource blocksERB1˜ERB2, and sends the transmitting end sequence TS2 in the echoresource blocks ERB3˜ERB5 via the transceiver 15. Finally, the processor13 receives the transmitting end sequence TS1 from the schedulingresource blocks SRB1˜SRB2 and receives the transmitting end sequence TS2from the scheduling resource blocks SRB3˜SRB5 via the transceiver 15again.

Please also refer to FIG. 3 for a sixth embodiment of the presentinvention. Different from the fifth embodiment, the D2D UE 1 is locatedin a network topology which has a maximum and farthest hop number of2N+1, where N is greater than 1. In this embodiment, besides furtherexecuting the operations (a)-(c) described in the fourth embodiment, theprocessor 13 further repeatedly executes the operations (b) and (c) forN−1 times after the operation (c).

Take a case where the D2D UE 1 is the transmitting end TX3 of the secondembodiment and N=2 as an example. The processor 13 receives thetransmitting end sequences TS2 and TS3 simultaneously from thescheduling resource block SRB1, receives the transmitting end sequenceTS3 from the scheduling resource block SRB2, and receives thetransmitting end sequences TS3 and TS4 simultaneously from thescheduling resource block SRB3 via the transceiver 15. Then, theprocessor 13 sends the transmitting end sequences TS1 and TS3 in theecho resource block ERB1, sends the transmitting end sequence TS3 in theecho resource block ERB2, and sends the transmitting end sequences TS3and TS4 in the echo resource block ERB3 via the transceiver 15.

Afterwards, the processor 13 receives the transmitting end sequence TS3from the scheduling resource block SRB2, receives the transmitting endsequences TS2 and TS3 simultaneously from the scheduling resource blockSRB3, receives the transmitting end sequences TS3 and TS4 simultaneouslyfrom the scheduling resource block SRB4, and receives the transmittingend sequence TS3 from the scheduling resource block SRB5 via thetransceiver 15. Then, the processor 13 sends the transmitting endsequence TS3 in the echo resource block ERB2, sends the transmitting endsequences TS2 and TS3 in the echo resource block ERB3, sends thetransmitting end sequences TS3 and TS4 in the echo resource block ERB4,and sends the transmitting end sequence TS3 in the echo resource blockERB5 via the transceiver 15. Finally, the processor 13 receives thetransmitting end sequence TS2 from the scheduling resource block SRB3,receives the transmitting end sequence TS3 from the scheduling resourceblocks SRB3˜SRB4, and receives the transmitting end sequence TS4 fromthe scheduling resource block SRB5 via the transceiver 15.

Similarly, besides further executing the aforesaid operations for N−1times, the processor 13 in other embodiments may further execute theaforesaid operations for M times more, where M is an adjustment numberand is a natural number. In other words, the processor 13 furtherrepeatedly executes the operations (b) and (c) for N+M−1 times after theoperation (c). As described above, the adjustment number M may bedecided by the backhaul network server and then informed to each of thetransmitting ends and the receiving ends; or may be decided by theprocessor 13 through executing an adjustment procedure.

A seventh embodiment of the present invention is shown in FIG. 4, whichis a flowchart diagram of a resource scheduling method. The resourcescheduling method is used for a D2D UE (e.g., either of the receivingends RX1 and RX2 of the first embodiment). The D2D UE is used in awireless communication system and is located in a network topology thatincludes a plurality of transmitting ends and a plurality of receivingends. The D2D UE is one of the receiving ends. The D2D UE comprises atransceiver, a storage and a processor. The storage is configured tostore a plurality of pieces of resource demand information and aplurality of priority values of the transmitting ends as well as aplurality of transmitting end sequences. Each of the transmitting endscorresponding to one of the transmitting end sequences. The wirelesscommunication system defines a scheduling channel, an echo channel and aplurality of data resource block sets. The scheduling channel comprisesa plurality of scheduling resource blocks, and the echo channelcomprises a plurality of echo resource blocks. The scheduling channeland the echo channel correspond to each other, and the schedulingresource blocks and the data resource block sets correspond to eachother. The resource scheduling method is executed by the processor.

Firstly, step 401 is executed to generate a first resource schedulingresult according to the resource demand information and the priorityvalue of each of the transmitting ends. Then, step 403 is executed tosend one of the transmitting end sequences respectively in thescheduling resource blocks via the transceiver according to the firstresource scheduling result. Then, step 405 is executed to receive atleast one of the transmitting end sequences respectively in the echoresource blocks via the transceiver.

Afterwards, step 407 is executed to generate a second resourcescheduling result according to the transmitting end sequences receivedfrom the echo resource blocks and the priority values. Next, step 409 isexecuted to send one of the transmitting end sequences respectively inthe scheduling resource blocks via the transceiver according to thesecond resource scheduling result.

Additionally, in other embodiments, the network topology has a maximumand farthest hop number of 2N+1, where N is a natural number. Theresource scheduling method of the present invention may further comprisethe following steps and the processor further executes the followingsteps for N−1 times, where i is 2 to N: receiving at least one of thetransmitting end sequences respectively in the echo resource blocks viathe transceiver; generating a (i+1)^(th) resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values; and sending one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the (i+1)^(th) resourcescheduling result.

Furthermore, in other embodiments, the network topology has a maximumand farthest hop number of 2N+1, where N is a natural number. Theresource scheduling method of the present invention may further comprisethe following steps and the processor further executes the followingsteps for N+M−1 times, where M represents an adjustment number and is anatural number, and i is 2 to N+M: receiving at least one of thetransmitting end sequences respectively in the echo resource blocks viathe transceiver; generating a (i+1)^(th) resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values; and sending one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the (i+1)^(th) resourcescheduling result.

In addition to the aforesaid steps, the resource scheduling method ofthis embodiment can also execute all the operations and have all thecorresponding functions set forth in the previous embodiments. How theresource scheduling method of this embodiment executes these operationsand have these functions will be readily appreciated by those ofordinary skill in the art based on the disclosures of the previousembodiments, and thus will not be further described herein.

An eighth embodiment of the present invention is shown in FIG. 5, whichis a flowchart diagram of a resource scheduling method. The resourcescheduling method is used for a D2D UE. The D2D UE is used in a wirelesscommunication system and is located in a network topology. The networktopology includes a plurality of transmitting ends and a plurality ofreceiving ends. The D2D UE is one of the transmitting ends (e.g., eitherof the transmitting ends TX1 and TX2 of the first embodiment). The D2DUE comprises a transceiver, a storage and a processor. The storage isconfigured to store a plurality of transmitting end sequences of thetransmitting ends. The wireless communication system defines ascheduling channel, an echo channel and a plurality of data resourceblock sets. The scheduling channel comprises a plurality of schedulingresource blocks, and the echo channel comprises a plurality of echoresource blocks. The scheduling channel and the echo channel correspondto each other, and the scheduling resource blocks and the data resourceblock sets correspond to each other. The resource scheduling method isexecuted by the processor.

Firstly, step 501 is executed to receive at least one of thetransmitting end sequences respectively from the scheduling resourceblocks via the transceiver. Then, step 503 is executed to transmit atleast one of the transmitting end sequences respectively in the echoresource blocks via the transceiver. The at least one transmitting endsequence transmitted in the echo resource blocks is the same as the atleast one transmitting end sequence received from the schedulingresource blocks. Afterwards, step 505 is executed to receive at leastone of the transmitting end sequences respectively from the schedulingresource blocks via the transceiver again.

In other embodiments, the network topology has a maximum and farthesthop number of 2N+1, where N is a natural number. The resource schedulingmethod of the present invention may further comprise the following stepof: repeatedly executing the step 503 and the step 505 for N−1 timesafter the step 505.

In other embodiments, the D2D UE has a maximum and farthest hop numberof 2N+1, where N is a natural number. The resource scheduling method ofthe present invention may further comprise the following step of:repeatedly executing the step 503 and the step 505 for N+M−1 times afterthe step 505, where M represents an adjustment number and is a naturalnumber.

In addition to the aforesaid steps, the resource scheduling method ofthis embodiment can also execute all the operations and have all thecorresponding functions set forth in the previous embodiments. How theresource scheduling method of this embodiment executes these operationsand have these functions will be readily appreciated by those ofordinary skill in the art based on the disclosures of the previousembodiments, and thus will not be further described herein.

According to the above descriptions, the resource scheduling mechanismof the present invention is adapted for a wireless communication systemadopting the OFDMA communication technology. This allows the D2D UEs toobtain wireless resources necessary for direct mode communication withadjacent D2D UEs in a distributed way and through two-dimensionaltime-frequency contention. Thereby, as compared with the conventionalcontending-for-scheduling mechanisms of the purely distributed type, thepresent invention can reduce the idle time and improve the spectrumutilization efficiency so as to improve the quality of service (QoS).

The above disclosure is related to the detailed technical contents andinventive features thereof. People skilled in this field may proceedwith a variety of modifications and replacements based on thedisclosures and suggestions of the invention as described withoutdeparting from the characteristics thereof. Nevertheless, although suchmodifications and replacements are not fully disclosed in the abovedescriptions, they have substantially been covered in the followingclaims as appended.

What is claimed is:
 1. A device-to-device (D2D) user equipment (UE) fora wireless communication system, the wireless communication systemdefining a scheduling channel, an echo channel and a plurality of dataresource block sets, the scheduling channel comprising a plurality ofscheduling resource blocks, the echo channel comprising a plurality ofecho resource blocks, the scheduling channel and the echo channelcorresponding to each other, the scheduling resource blocks and the dataresource block sets corresponding to each other, the D2D UE beinglocated in a network topology that includes a plurality of transmittingends and a plurality of receiving ends, and the D2D UE being one of thereceiving ends, the D2D UE comprising: a transceiver; a storage, beingconfigured to store a plurality of pieces of resource demand informationand a plurality of priority values of the transmitting ends, and aplurality of transmitting end sequences, wherein each of thetransmitting ends corresponds to one of the transmitting end sequences;and a processor electrically connected to the transceiver and thestorage, being configured to execute the following operations:generating a first resource scheduling result according to the resourcedemand information and the priority value of each of the transmittingends; sending one of the transmitting end sequences respectively in thescheduling resource blocks via the transceiver according to the firstresource scheduling result; receiving at least one of the transmittingend sequences respectively in the echo resource blocks via thetransceiver; generating a second resource scheduling result according tothe transmitting end sequences received from the echo resource blocksand the priority values; and sending one of the transmitting endsequences respectively in the scheduling resource blocks via thetransceiver according to the second resource scheduling result.
 2. TheD2D UE of claim 1, wherein the network topology has a maximum andfarthest hop number of 2N+1, where N is a natural number, and theprocessor is further configured to execute the following operations forN−1 times, where i is 2 to N: receiving at least one of the transmittingend sequences respectively in the echo resource blocks via thetransceiver; generating a (i+1)^(th) resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values; and sending one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the (i+1)^(th) resourcescheduling result.
 3. The D2D UE of claim 2, wherein the transmittingends and the receiving ends connect to a backhaul network server, andthe backhaul network server decides the maximum and farthest hop numberand informs the transmitting ends and the receiving ends of the maximumand farthest hop number.
 4. The D2D UE of claim 1, wherein there is amaximum and farthest hop number of 2N+1, where N is a natural number,and the processor is further configured to execute the followingoperations for N+M−1 times, where M represents an adjustment number andis a natural number, and i is 2 to N+M: receiving at least one of thetransmitting end sequences respectively in the echo resource blocks viathe transceiver; generating a (i+1)^(th) resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values; and sending one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the (i+1)^(th) resourcescheduling result.
 5. The D2D UE of claim 4, wherein the transmittingends and the receiving ends connect to a backhaul network server, andthe backhaul network server decides the maximum and farthest hop numberand the adjustment number, and informs the transmitting ends and thereceiving ends of the maximum and farthest hop number and the adjustmentnumber.
 6. The D2D UE of claim 4, wherein the processor executes anadjustment procedure to decide the adjustment number.
 7. A resourcescheduling method for a device-to-device (D2D) user equipment (UE), theD2D UE being used in a wireless communication system and being locatedin a network topology that includes a plurality of transmitting ends anda plurality of receiving ends, the D2D UE being one of the receivingends and comprising a transceiver, a storage and a processor, thestorage being configured to store a plurality of pieces of resourcedemand information of the transmitting ends, a plurality of priorityvalues of the transmitting ends and a plurality of transmitting endsequences, each of the transmitting ends corresponding to one of thetransmitting end sequences, the wireless communication system defining ascheduling channel, an echo channel and a plurality of data resourceblock sets, the scheduling channel comprising a plurality of schedulingresource blocks, the echo channel comprising a plurality of echoresource blocks, the scheduling channel and the echo channelcorresponding to each other, the scheduling resource blocks and the dataresource block sets corresponding to each other, the resource schedulingmethod being executed by the processor, the method comprising:generating a first resource scheduling result according to the resourcedemand information and the priority value of each of the transmittingends; sending one of the transmitting end sequences respectively in thescheduling resource blocks via the transceiver according to the firstresource scheduling result; receiving at least one of the transmittingend sequences respectively in the echo resource blocks via thetransceiver; generating a second resource scheduling result according tothe transmitting end sequences received from the echo resource blocksand the priority values; and sending one of the transmitting endsequences respectively in the scheduling resource blocks via thetransceiver according to the second resource scheduling result.
 8. Theresource scheduling method of claim 7, wherein the network topology hasa maximum and farthest hop number of 2N+1, where N is a natural number,and the resource scheduling method further comprises the following stepsand the processor further executes the following steps for N−1 times,where i is 2 to N: receiving at least one of the transmitting endsequences respectively in the echo resource blocks via the transceiver;generating a (i+1)^(th) resource scheduling result according to thetransmitting end sequences received from the echo resource blocks andthe priority values; and sending one of the transmitting end sequencesrespectively in the scheduling resource blocks via the transceiveraccording to the (i+1)^(th) resource scheduling result.
 9. The resourcescheduling method of claim 8, wherein the transmitting ends and thereceiving ends connect to a backhaul network server, and the backhaulnetwork server decides the maximum and farthest hop number and informsthe transmitting ends and the receiving ends of the maximum and farthesthop number.
 10. The resource scheduling method of claim 7, wherein thenetwork topology has a maximum and farthest hop number of 2N+1, where Nis a natural number, and the resource scheduling method furthercomprises the following steps and the processor further executes thefollowing steps for N+M−1 times, where M represents an adjustment numberand is a natural number, and i is 2 to N+M: receiving at least one ofthe transmitting end sequences respectively in the echo resource blocksvia the transceiver; generating a (i+1)^(th) resource scheduling resultaccording to the transmitting end sequences received from the echoresource blocks and the priority values; and sending one of thetransmitting end sequences respectively in the scheduling resourceblocks via the transceiver according to the (i+1)^(th) resourcescheduling result.
 11. The resource scheduling method of claim 10,wherein the transmitting ends and the receiving ends connect to abackhaul network server, and the backhaul network server decides themaximum and farthest hop number and the adjustment number, and informsthe transmitting ends and the receiving ends of the maximum and farthesthop number and the adjustment number.
 12. The resource scheduling methodof claim 10, further comprising executing an adjustment procedure todecide the adjustment number.
 13. A device-to-device (D2D) userequipment (UE) for a wireless communication system, the wirelesscommunication system defining a scheduling channel, an echo channel anda plurality of data resource block sets, the scheduling channelcomprising a plurality of scheduling resource blocks, the echo channelcomprising a plurality of echo resource blocks, the scheduling channeland the echo channel corresponding to each other, the schedulingresource blocks and the data resource block sets corresponding to eachother, the D2D UE being located in a network topology that includes aplurality of transmitting ends and a plurality of receiving ends, andthe D2D UE being one of the transmitting ends, the D2D UE comprising: atransceiver; a storage, being configured to store a plurality oftransmitting end sequences, wherein the D2D UE corresponds to one of thetransmitting end sequences; and a processor electrically connected tothe transceiver and the storage, being configured to execute thefollowing operations: (a) receiving at least one of the transmitting endsequences respectively from the scheduling resource blocks via thetransceiver; (b) sending at least one of the transmitting end sequencesrespectively in the echo resource blocks via the transceiver, whereinthe at least one transmitting end sequence transmitted in the echoresource blocks is the same as the at least one transmitting endsequence received from the scheduling resource blocks; and (c) receivingat least one of the transmitting end sequences respectively again fromthe scheduling resource blocks via the transceiver.
 14. The D2D UE ofclaim 13, wherein the network topology has a maximum and farthest hopnumber of 2N+1, where N is a natural number, and the processor isfurther configured to repeatedly execute the operations (b) and (c) forN−1 times after the operation (c).
 15. The D2D UE of claim 14, whereinthe transmitting ends and the receiving ends connect to a backhaulnetwork server, and the backhaul network server decides the maximum andfarthest hop number and informs the transmitting ends and the receivingends of the maximum and farthest hop number.
 16. The D2D UE of claim 13,wherein the network topology has a maximum and farthest hop number of2N+1, where N is a natural number, and the processor is furtherconfigured to repeatedly execute the operations (b) and (c) for N+M−1times after the operation (c), where M represents an adjustment numberand is a natural number.
 17. The D2D UE of claim 16, wherein thetransmitting ends and the receiving ends connect to a backhaul networkserver, and the backhaul network server decides the maximum and farthesthop number and the adjustment number, and informs the transmitting endsand the receiving ends of the maximum and farthest hop number and theadjustment number.
 18. The D2D UE of claim 16, wherein the processorfurther executes an adjustment procedure to decide the adjustmentnumber.
 19. A resource scheduling method for a device-to-device (D2D)user equipment (UE), the D2D UE being used in a wireless communicationsystem and being located in a network topology that includes a pluralityof transmitting ends and a plurality of receiving ends, the D2D UE beingone of the transmitting ends and comprising a transceiver, a storage anda processor, the storage being configured to store a plurality oftransmitting end sequences, the D2D UE corresponding to one of thetransmitting end sequences, the wireless communication system defining ascheduling channel, an echo channel and a plurality of data resourceblock sets, the scheduling channel comprising a plurality of schedulingresource blocks, the echo channel comprising a plurality of echoresource blocks, the scheduling channel and the echo channelcorresponding to each other, the scheduling resource blocks and the dataresource block sets corresponding to each other, the resource schedulingmethod being executed by the processor, the method comprising: (a)receiving at least one of the transmitting end sequences respectivelyfrom the scheduling resource blocks via the transceiver; (b)transmitting at least one of the transmitting end sequences respectivelyin the echo resource blocks via the transceiver, wherein the at leastone transmitting end sequence transmitted in the echo resource blocks isthe same as the at least one transmitting end sequence received from thescheduling resource blocks; and (c) receiving at least one of thetransmitting end sequences respectively again from the schedulingresource blocks via the transceiver.
 20. The resource scheduling methodof claim 19, wherein the network topology has a maximum and farthest hopnumber of 2N+1, where N is a natural number, and the resource schedulingmethod further comprises the following step of: repeatedly executing thestep (a) and the step (b) for N−1 times after the step (c).
 21. Theresource scheduling method of claim 20, wherein the transmitting endsand the receiving ends connect to a backhaul network server, and thebackhaul network server decides the maximum and farthest hop number andinforms the transmitting ends and the receiving ends of the maximum andfarthest hop number.
 22. The resource scheduling method of claim 19,wherein the network topology has a maximum and farthest hop number of2N+1, where N is a natural number, and the resource scheduling methodfurther comprises the following step of: repeatedly executing the step(b) and the step (c) for N+M−1 times after the step (c), where M is anadjustment number and is a natural number.
 23. The resource schedulingmethod of claim 22, wherein the transmitting ends and the receiving endsconnect to a backhaul network server, and the backhaul network serverdecides the maximum and farthest hop number and the adjustment number,and informs the transmitting ends and the receiving ends of the maximumand farthest hop number and the adjustment number.
 24. The resourcescheduling method of claim 22, further comprising executing anadjustment procedure to decide the adjustment number.